PURPOSE: To obtain titled catalyst inexpensively having high activity and wide range of application by supporting superfine particles of metal, alloy or compound obtd. by gaseous phase chemical reaction between vapor contg. metallic halide and reducing gas on ceramic carrier of catalyst.

CONSTITUTION: Superfine particles having ≤1,000 particle size are obtd. stably by gaseous phase chemical reaction of halide wherein vapor contg. at least one kind of metallic halide such as halide of Fe, Co, or Ni, etc. is introduced together with reducing gas such as H2 with different introducing speed to each other causing laminar contact with each other. Superfine particles prepd. in this way are supported by the ceramic carrier. Obtd. catalyst is inexpensive and has high catalytic activity, maintains performance stably for long time use and is applicable to wide range of conditions sufficient as three component catalyst for the purification of exhaust gas of automobile.